Herbicidal grease composition



United States Patent HERBI CI DAL GREASE COMPOSITION Jelfrey H.Bartlett, Westfield, William H. Brugmann, Jr.,

Middlesex, and Arnold J. Moi-way, Clark, N. J., assignors to EssoResearch and Engineering Company, a corporation of Delaware No Drawing.Application December 19, 1955 Serial No. 553,718

6 Claims. (Cl. 712.6)

This invention relates to grease compositions contain ing salts ofhalogenated aryloxyalkyl carboXylic acids, and to their use as brushkillers and the like.

This application is a continuation-in-part of Serial No; 473,451, filedDecember 6, 1954.

The herbicidal and arboricidal activity of various phenoxy carboxylicacid esters such as the octyl ester of 2,4-dichloroor2,4,5-trichlorophenoxyacetic acid is wellknown. Consequently, suchagents have been heretofore incorporated in weed and brush killerformulations of the aqueous emulsion or oil spray type. On the otherhand the use of salts of these chlorphenoxycarboxylic acids has notpreviously found much favor in floricidal spray or dusting formulations,despite the fact that intrinsic-ally such salts are substantially morepotent than the corresponding esters while at the same time beingconsiderably cheaper than the latter. Of course, the main reason why thesalts, as well as the acids themselves, have been found unsatisfactoryhas been their solubility in water which results in their being tooreadily leached from or washed off the original point of application byrain, irrigation, etc. Thus, when applied as a spray, they frequentlycause only temporary top kill because their residual toxicity period istoo short to permit translocation of the active agent into the plantroots. In addition, the dissolved salts may cause injury to valuablecrops or plants onto which they may be carried in the rain Water afterbeing washed off the fiora whose kill was desired.

Furthermore, even the formulations employing the essentially waterinsoluble esters have been subject to serious drawbacks. The foremost ofthese is their tendency, due to their considerable volatility, todri-ft? or wander from the original point of application to contiguousareas where they may cause serious injury to sensitive crops such ascotton. The volatility of the esters also reduces the residual activityof the floricide and hence the intended weed control is not solong-lasting as desired. The previously known 2,4-'-D and 2,4,5-T typesprays or dusting formulas frequently have also caused injury tovaluable plants by driftin or being accidentally blown to adjacent areaseven in the course of the original spraying or dusting operation.Consequently, because of the dif- Patented Jan. 6, 1959 brushing ordau'bing the fioricidal (plant-killing) compound onto specific weeds,plants or trees. On the other hand, such ester containing grease-likeformulations still are not only rather costly but also relativelynonpermanent, due to the substantial volatility of the esters as well asthe relative ease with which the floricidecontaining oil base is leachedout from such greases.

It is an object of the present invention to provide nonvolatile,long-persistent floricidal compositions by employing salts ofhalogenated aryloxyalkyl carboxylic acids. Another object is to providegrease-like compositions comprising a normally liquid. hydrocarbon oilbase and thickened to a grease-like consistency with the aid of acomplex-like thickener containing a soap 'of a higher fatty acid incombination with a floricidal amount of a salt of a chlorinatedphenoxycarboxylic acid. These andother objects, as well as the nature,operation and advantages of the invention will become more clearlyapparent from the subsequent description.

It has now been discovered that highly effective floricidal compositionscan be formulated'from salts of halogenated aryloxyalkyl carboxylicacids by dispersing them with a conventional thickener in a normallyliquid base such as a hydrocarbon oil or a synthetic ester base, therebyforming an adhesive grease wherein the fioricidal agent is in anunusually permanent form. The salts of halogenated aryl oxyalkylcarboxylic acids, being mild soaps as well as fioricides, themselvesserve as a co thickener as well as a fioricidal compound. Thus, theconventional thickener requirement is substantially reduced by thiscooperation of the herbicidal carboxylic acid salt.

The terms floricidal and herbicidal will be used interchangeably hereinto denote the ability of a composition to kill or inhibit the growth ofany undesirable plant, including trees, shrubs, herbs and similar Weedsand the like.

Suitable as the fioricidal salts in the practice of this invention arethe various salts of halogenated aryloxyalkyl carboxylic acids. Amongthe metal salts those of mono and divalent metals such as sodium,potassium,

lithium, calcium, and barium, deserve particular mention,

ficulty of applying them with the desired degree of-selecreduce thevolatility-of the active esters but also permit though salts ofaluminum, copper, lead, and the like can be used also. Furthermore, thepresent invention is especially noteworthy in that it permits the use ofthe relatively inexpensive water soluble salts such as those of sodiumor potassium in fioricides which have a high degree of persistency aswell as excellent water resistance, due to the protective action of theother components present. Such greases are substantially water insolubleup 'to On the basis of cost, the sodium salts are therefore especiallyadvantageous, though the more water resistant lithium or calcium saltsmay be preferred where especially high resistance to rain water and thelike is desired.

' The acid portion of the floricidal soap is derived from a halogenatedaryloxyalkyl carboxylic acid, among which 2,4dichlorophenoxyacetie and2,4,S-trichlorophenoxyacetic acid are particularly preferred. However,the corresponding brominated or iodinated derivatives, as well asgenerally halogenated phenoXy compounds having an aliphatic acidsubstituent of about 1 to 3 carbon atoms, e. -g a propionic acid radicalor an ethyl sulfate radical, may be similarly useful. In other words,examples of suitable floricidal soaps include sodium 2,4-dichlorophenoxyacetate, lithium 2,4,5 -trichlorophenoxy-acetate, calcium salt of2,,4-dichlorophenoXy-ethyl sulfate, etc.,

v The oil base useful herein may be a mineral oil ranging in viscositybetween about 35 and 200 'SSU (Saybolt seconds Universal) /210 F. orbetween about 50 and 2,000 SSU/'10 O F., cold sett" type basescomprising rosin oil, synthetic ol ester bases, etc. However,compositions compr'ising mineral oil are preferred.

The soaps or salts required herein may of course be preformed prior tobeing dispersed in the oil base or they may be formed in situ byreacting the free acid and a suitable basic compound after beingdispersed in the oil, various such methods being well known in thegrease making art. Furthermore, rather than forming a neutral soap, itis also possible to have an excess of up to about 2% of the free acidpresent, as long as enough soap or other thickening agent is dispersedin the oil base to give it the desired grease structure or consistency.Too much free acid tends to impair the solid grease structure. On theother hand, a moderate excess of free alkali is generally permissible,and frequently may be desirable, especially when pentachlorophenol,maleic hydrazide or other materials are added as synergists or for otherpurposes.

The amount of the floricidal haloacid salt may range from about 0.5 tobased on the oil, depending on the desired degree of fioricidal activityand grease consistency. Actually, since thickened grease compositionstend to adhere firmly at the point of original application,concentrations of about 0.5 to 2% of the floricidal chloroacid compoundare frequently sufiicient to-achieve the desired floricidal effect, andit may therefore sometimes be. economical to use only such small amountsof the fioricide in the grease. However, these small amounts aregenerally insufficient to cooperate with the conventional thickener indeveloping the desired complex-like grease structure and consequentlythe preferred embodiments of this invention contain at least 1%, andpreferably 2 to 8% of the floricidal salt, based on the oil, in order toachieve a high degree of permanence with a minimum amount of theconventional thickener.

In addition to the floricidal salt, the compositions of this inventioncontain a conventional grease thickener, preferably one with which thechloroacid salt can develop a complex-like structure. Suitablethickeners include the metal salts of the higher fatty acids orhydroxysubstituted fatty acids, especially those of about 12 to 20carbon atoms, e. g. the alkali metal or alkaline earth duce a greasecharacterized by a penetration value of about 275 to 370 mm./ 10unworked and a dropping point of at least .300" F in order to assure asuitable degree of adhes-iveness and guard against too easy melting inthe sun.

In addition, of course, the compositions of this invention may containother ingredients conventionally incorporated in grease, e. g.anti-oxidants such as phenyl-alphanaphthylamine, structure modifiers,graphite, sulfurized fatty oils and other load-carrying agents,corrosion inhibitors, metal deactivators, etc. For instance, theaddition of a small amount of a stringiness agent such as the variousknown olefinic polymers of 20,000 to 200,000 molecular weight, e. g.about 0.001% of 50,000 M. W. polybutene, may be desirable in givinggreater adhesiveness and stickiness. Also, the addition of small amountsof corrosion inhibitors, e. g. sorbitan monooleate or oleic or otherpartial esters of pentaerythritol may be highly advantageous where thegrease composition is dispensed from metal applicators or used tolubricate metal parts. Formulation of such a well-balanced grease may beespecially advantageous for farm use since it will permit vExample 1 5parts of 2,4-dichlorophenoxyacetic acid and 15 parts of essentiallysaturated hydrogenated fish oil acid of about 18 carbon atoms permolecule were mixed with 75.7 parts of a hydrofined coastal typepetroleum distillate characterized by a viscosity of 55 SSU/210 F. and500 metal salts of hydrogenated fish oil acids having a molecular weightand saturation substantially equivalent to stearic acid, sodiumstearate, lithium hydroxystearate, potassium laurate, calcium palmitate,sodium oleate, the lithium salt of tall oil acid, and similar soapswell-known in the grease making art. Enough thickener is provided in thecomposition to produce the desired consistency, e. g. about 3 to basedon the oil, the amount depending upon the amount of floricidalchloroacid salt present to act as a co-thickener. However, in order toproduce the optimum grease structure or complex, in accordance with thisinvention it is desirable to provide about 1 to 4 moles, preferablyabout 2 to 3 moles of the higher fatty acid soap per mole of thefloricidal chloroacid salt present. Non-soap thickeners such as carbonblack, finely divided silica, attapulgite, bentonite reacted with aquaternary ammonium base, etc., may be useful also.

Generally speaking the preferred compositions of this invention have theadvantage that, due to the stable fibrous structure set up by thecomplex-like combination of fioricidal salt and higher fatty acids soap,the floricidal agent will stay behind as a solid residue on the weed orbrush stalks even if rain leaches out the oil or other liquid base. Incontrast, in previously described herbicidal greases or pastes theherbicidal agent generally was dissolved in the base and therefore waswashed away in it.

'In general it is desirable to use the oil base and one or morethickening agents in such a combination as to pro- SSU/ 100 F. Themixture was heated to 150 'F. in a fire heated kettle. 38 parts of a 10%aqueous solution of lithium monohydrate was then added and thetemperature raised to 400 F. with stirring, thereby neutralizing thefree acids in the oil. Finally, 0.5 part of phenyl alpha naphthylaminewas added to the hot mix and the molten mix was cooled by pouring intopans. The cold, solid, grease cake was then broken up and homogenized toyield a smooth, adhesive, uniform product having the followingproperties:

Appearance Excellent smooth adhesive product. Penetration at 77 F., mm.:

Unworked 23.4. Worked, 60 strokes 27.5. Worked, 100,000 strokes 28.0.Water solubility (boiling water) Nil. Dropping point, F. 360. NormaHoifmann oxidation test, hours to 5 p. s. i. g. drop in oxygen pressure'275.

The data indicate that the product, wherein a chlorinated aromatic acidforms part of a complex thickener,

Example 2 To further illustrate the utility of the invention, 75 partsof the grease of Example 1 were mixed with 25 parts of a motor oil blendcomposed of bright stock and high viscosity index phenol extracteddistillate. The motor oil blend had a viscosity of 435 SSU/100 F. and aflash point of 450 F. Upon homogenizing the mixture, the followingproduct was obtained:

Appearance Excellent smooth uniform adhesive product.

Penetration, 77 F., mm.:

Unworked 29.5. Worked, 60 strokes 31.0. Worked, 100,000 strokes v 33.0.Dropping point, F 360.

It is interesting to note that the dropping point of this grease is thesame as in Example 1, despite the higher oil content of the former.This, of course, is indicative of the fact that the soap fibers orcomplexes which hold the oil are determinative of the dropping point ofthe grease system, independently of the amount of oil so held.

Example 2 also shows that greases compounded according to this inventioncan be easily diluted to any desired consistency, e. g. with regularcrank case oil or even with drainings. This further increases the wideutility of the product on the farm or for other eventual users.

Having described the general nature, preparation, examples andadvantages of the invention, its scope is particularly pointed out inthe appended claims.

What is claimed is:

1. A herbicidal grease composition having an unworked penetration valueof at least 27.5 mm. which comprises a mineral oil base normally havinga viscosity of about 50 to 2000 SSU at 100 F., said oil base beingthickened by a herbicidal thickener finely dispersed therein to formsaid grease composition, said thickener comprising the combination of0.5 to wt. percent, based on the oil base, of a herbicidal salt of ahalogenated aryloxy compound having an aliphatic acid substituent of 1to 3 carbon atoms and about 3 to 50 wt. percent, based on the oil, of asoap selected from the group consisting of alkali and alkaline earthmetal soaps of C to C fatty acids.

2. A herbicidal grease composition having an unworked penetration valueof at least 27.5 mm. which comprises a hydrocarbon oil base normallyhaving a viscosity of to 2000 SSU at F., said oil base being thickenedby a herbicidal thickener finely dispersed therein to form said greasecomposition, said thickener comprising the combination of 2 to 8 wt.percent, based on the oil base, of a herbicidal metal salt of achlorocompound of the class consisting of 2,4-dichlorophenoxyaceticacid, 2,4-dichlorophenoxypropionic acid, 2,4,5-trichlorophenoxy aceticacid, and 2,4-dichlorophenoxy ethyl sulfate, and l to 4 moles per moleof said herbicidal metal salt of a metal salt of a fatty acid having 12to 20 carbon atoms per molecule, wherein said metals are selected fromthe class consisting of alkali and alkaline earth metals.

3. A herbicidal composition according to claim 2 wherein the fatty acidsalt is an alkali metal salt of hydroxy-stearic acid.

4. A herbicidal composition according to claim 2 wherein thechlorocompound salt is the lithium salt of 2,4-dichlorophenoxy aceticacid.

5. A herbicidal composition according to claim 4 wherein the fatty acidsalt is a lithium soap of a hydrogenated fish oil acid of about 18carbon atoms per molecule.

6. A grease composition which comprises 100 parts of a mineral oil basenormally having a viscosity of about 500 SSU at 100 F., said oil basebeing thickened to a grease consistency corresponding to an unworkedpenetration value of at least 27.5 mm. by having dispersed therein aherbicidal thickener comprising the combination of about 2 to 8 parts oflithium, 2,4-dichlorophenoxyacetate and about 2 to 3 moles per moleacetate of the lithium soap of hydrogenated fish oil acids.

References Cited in the file of this patent UNITED STATES PATENTS1,999,524 Molin Apr. 30, 1935 2,326,471 Lontz Aug. 10, 1943 2,417,264Morway et al Mar. 11, 1947 2,580,653 Bridgeman Jan. 1, 1952

1. A HERBICIDAL GREASE COMPOSITION HAVING AN UNWORKED PENETRATION VALUEOF AT LEAST 27.5 MM. WHICH COMPRISES A MINERAL OIL BASE NORMALLY HAVINGA VISCOSITY OF ABOUT 50 TO 2000 SSU AT 100*F., SAID OIL BASE BEINGTHICKENED BY A HERBICIDAL THICKENER FINELY DISPERSED THEREIN TO FORMSAID GREASE COMPOSITION, SAID THICKENER COMPRISING THE COMBINATION OF0.5 TO 10WT. PERCENT, BASED ON THE OIL BASE, OF 3 HERBICIDAL SALT OF AHALOGENATED ARYLOXY COMPOUND HAVING AN ALIPHATIC ACID SUBSTITUENT OF 1TO 3 CARBON ATOMS AND ABOUT 3 TO 50WT. PERCENT, BASED ON THE OIL, OF ASOAP SELECTED FROM THE GROUP CONSISTING OF ALKALI AND ALKALINE EARTHMETAL SOAPS OF C12 TO C20 FATTY ACIDS.